CASE STUDY 300 words

 You have been given the responsibility to set up an office environment composed of 15 computers and install appropriate operating systems in those. However, you have also been advised to keep the sourcing cost of these OS to as minimum as possible; at the same time, ensuring user experience is reasonably good and the users, who are mostly non-technical, should be able to navigate the systems rather easily. Its an accounting farm and they will only use the computers for regular accounting related activities, emailing, and a bit of spreadsheet and documentation. Write down in your word out of Windows, Linux and MacOS, which one will you recommend for the setup of the computers and why; it could also be a mixed system. State your reasons clearly for your choice. The marking on this question will be done based on the soundness of your logic, so theres no specific right and wrong answer.